Pykrolidino ketones



United States Patent 1 15 Claims. ci. 260-3265) R is selected from the group consisting of hydrogen, lower alkyl, lower alkoxy, hydroxyl and halogen,

R is selected from the group consisting of alkyl with 2 to 3 carbon atoms and alkenyl with 2 to 8 carbon atoms, an

R" is selected from the group consisting of hydrogen and lower alkyl,

and their nontoxic, pharmacolo-gically acceptable acid addition salts.

The Ot-PYITOlldlIlO ketones of the Formula I above may be prepared by a variety of methods, of which the following has been found to be most convenient:

By reacting an u-ha'lo ketone of the formula Hal (II) wherein Hal is halogen and R and R have the meanings defined previously in connection with Formula I, with a pyrrolidine of the formula N I i (III) wherein R" has the meanings previously defined in connection with Formula I. The reaction between compounds II and III is advantageously performed at room temperature or slightly elevated temperature in the presence of an inert organic solvent, such as benzene, toluene, ether, acetone, carbon tetrachloride, chloroform and the like, as well as in the presence of an organic or inorganic substance capable of neutralizing or typing up the hydrogen halide formed during the reaction, such as pyridine, quinoline, N-dialkylanilines, or alkali metal carbonates, such as sodium bicarbonate, potassium carbonate and the like. However, the pyrrolidine reactant itself may also be employed to serve as the hydrogen halide neutralizing agent; for this purpose the pyrrolidine compound of the Formula III is provided in the reaction mixture in an amount which is sufiicient to make available wherein 3,314,970 Patented. Apr. 18, 1967 not only the stoichiometric molar quantity for reaction with the vt-halo ketone II but also the stoichiometric molar quantity for neutralization of. the theoretical amount of hydrogen halide formed during the reaction. The ot-halo ketones of the Formula II which are used as starting materials in this method are either well known compounds or may be prepared by known methods, such as by bromination of the corresponding ketones in glacial acetic acid according to Schmidt, Berichte der Deutschen Chemischen Gesellschaft, vol. 22, page 3251 (1889).

EXAMPLE 1 Preparation 0 a-pyrrolidino-valerophenone and acid addition salts thereof (a) A solution of 19.2 gm. of a-bromo-valerophenone (B.P. C. at 1 mm. Hg) in 40 cc. of benzene was added dropwise at a temperature of about 40 C., while stirring, to a solution of 11.2 gm. of pyrrolidine in 40 cc. of benzene. After all of the u-halo ketone solution had been added, the reaction mixture was stirred for thirty minutes more and was then allowed to stand for several hours. Thereafter, the benzene was distilled off in vacuo, and the residue was taken up in dilute hydrochloric acid. The acid solution was extracted twice by shaking with ether. The ether extract solutions were discarded. The aqueous acid solution was made alkaline with sodium hydroxide, whereby a precipitate formed. This precipitate was taken up in ether, the ether solution was dried over sodium sulfate, and then the ether was evaporated. The residue was distilled in vacuo, which yielded 18 gm. of raw wpyrrolidino-valerophenone of the In analogous fashion the following other acid addition salts of twpyrrolidino-valerophenone were prepared:

(1) Acid sulfate, M.P. C. (recrystallized from isopropanol).

(2) Maleate, M.P. 131 C. (recrystallized from acetone).

(3) Tartrate, M.P. 148-149 C. (recrystallized from isopropanol).

(4) Citrate, M.P. 88 C. with decomposition (recrystallized from acetone).

(b) A solution of 24 gm. of et-bromo valerophenone in 50 cc. of carbon tetrachloride was added dropwise to 15 gm. of pyrrolidine, accompanied by stirring. During this dropwise addition of the u-halo-ketone solution the temperature of the reaction mixture was allowed to rise to 40 C., and after all of the solution had been added the reaction mixture was stirred for four hours more. The reaction mixture was then worked up as described under (a) above. The yield of a-pyrrolidino-valerophenone was 20 gm. It had a boiling point of 116 C. at 0.2 mm. Hg.

(c) A solution of 24 gm. of a-bromo-valerophenone in 50 cc. of chloroform were added dropwise, accompanied by stirring, to a solution of 8 gm. of pyrrolidine and 9 gm. of sodium bicarbonate in 25 cc. of chloroform. After all of the u-halo-ketone solution had been added the reaction mixture was stirred for two hours more and was then allowed to stand overnight. Thereafter, the reaction mixture was worked up as described under (a) above. The yield of ot-pyrrolidino-valerophenone was 16 gm.

The same result was obtained when acetone was used as the solvent instead of chloroform.

(d) A solution of 4 gm. of pyrrolidine and v gm. of pyridine in 20 cc. of ether was allowed to flow slowly into a solution of 13 gm. of a-bromowalerophenone in ml. of ether, accompanied by constant stirring. After all of the pyrrolidine-pyridine solution had been added the reaction mixture was stirred for two hours more and was then worked up as described under (a) above. The yield of a-pyrrolidino-valerophenone was 7 gm.

EXAMPLE 2 Preparation of I-(p-methyl-phenyl)-2-pyrrolidinopentanone-(I) A solution of 28.6 gm. of pyrrolidine in 100 cc. of benzene was added dropwise at a temperature of -40 C. to a solution of 25.6 gm. of l-(p-methyl-phenyD-Z- bromo-pentanone-(1) (boiling point 8788 C. at 0.02 mm. Hg) in 80 ml. of benzene, accompanied by stirring. The resulting reaction mixture was then stirred for five hours more at room temperature, and it was then worked up as described in Example 1(a). 20 gm. of the ocpyrrolidino ketone of the formula CHz--C0-(]JHCHa-CH1-CH:

were obtained. The product had a boiling point of 104 C. at 0.08 mm. Hg.

The free base was converted into its hydrochloric acid addition salt by adding ethereal hydrochloric acid to a solution of the free base in ether. After recrystallization from methyl ethyl ketone the hydrochloride had a melting point of 174176 C.

EXAMPLE 3 Preparation of 1-phenyl-2-pyrr0lidino-3-methyl butanone-(1 A solution of 35 gm. of pyrrolidine in 100 cc. of benzene was added dropwise at room temperature, accompanied by stirring, to a solution of 42 gm. of abromo-isovalerophenone in 100 cc. of benzene. After all of the pyrrolidine solution had been added the reaction mixture was heated for two hours at 3540 C. and was then allowed to stand overnight at room temperature. Thereafter, it was worked up as described in Example 1 (a). 10 gm. of the a-pyrrolidino ketone of the formula were obtained. It had a boiling point of 126 C. at 0.5 mm. Hg.

Its hydrochloride had a melting point of 225-226 C. after recrystallization from a mixture of acetone and ethanol.

EXAMPLE 4 (a) Preparation of 1-(p-rneth0xy-phenyl)-2- V pyrrolidz'no-pentanone-(I 20 gm. of l-(p-methoxy-phenyl)-2bromopentanone- (1) (B.P. 156 C. at 0.8 mm. Hg) were reacted with 22.4 gm. of pyrrolidine by a procedure analogous to that described in the preceding example. pyrrolidino ketone of the formula cH3-0 -o O-(FH-OHn-OHa-OH:

were obtained. It had a boiling point of 147 C. at 0.25

mm. Hg. Its hydrochloride had a melting point of 176- 178 C. after recrystallization from methyl ethyl ketone.

(b) Preparation of1-(p-hydroxy-phenyl)-2-pyrr0lidin0- pentanone- (1 5 gm. of the ketone obtained under (a) above were admixed with 15 cc. of glacial acetic acid and 10 cc. of 70% hydrogen iodide, and the resulting mixture was refluxed for one and a half hours. Thereafter, the reaction mixture was allowed to cool, water was added and the aqueous mixture was extracted by shaking with ether. The ether extract solution was discarded. The aqueous phase was made alkaline with ammonia, whereby a precipitate formed which was identified to be the ot-pyrrolidino ketone of the formula 22.6 gm. of a-bromo-butyrophenone (B.P. 98 C. at 0.8 mm. Hg) were reacted with 28.4 gm. of pyrrolidine by a method analogous to that described in Example 2. The yield was 15 gm. of the a-pyrrolidino ketone of the formula -o0-o11-oHl-orn having a boiling point of 94 C. at 0.05 mm. Hg. Its

hydrochloride had a melting point of 196-198 C. after recrystallization from methyl ethyl ketone.

EXAMPLE 6 Preparation of l-phenyl-2-pyrrolidino-heptanane-(1 27 gm. of 1-phenyl-2-bromo-heptanone-(1) (B.P. 126- 132 C. at 0.3 mm. Hg) were reacted with 14.2 gm. of pyrrolidine in benzene as a solvent, in a manner analogous to that described in Example 2. The yield was 15 gm. of the u-pyrrolidino ketone of the formula Q-oo-oH-oHloH,-omo1rlo1n having a boiling point of 136-140" C. at 0.1 mm. Hg. Its hydrochloride, recrystallized from a mixture of acetone 14 gm. of the OL- and ethanol, was obtained in the form of colorless crystals having a melting point of 158 C.

EXAMPLE 7 Preparation of l-(p-chloro-phenyl) -2-pyrrolidinopentanone-(l Using a procedure analogous to that described in Example 2, 27.5 gm. of 1-(p-chloro-phenyl)-2-bromopentanone-(l) (B.P. 114 C. at 0.2 mm. Hg) were reacted with 28.4 gm. of pyrrolidine, yielding 18 gm. of the a-pyrrolidine, yielding 18 gm. of the a-pyrrolidino ketone of the formula having a boiling point of 126-130 C. at 0.1 mm. Hg. Its hydrochloride was obtained in the form of colorless crystals having a melting point of 205-207 C. after recrystallization from acetone.

EXAMPLE 8 Preparation of 1(m-methyl-phenyl) -2-pyrrolidt'n0- pentanone-(I Using a procedure analogous to that described in Example 2, 12.5 gm. of 1-(m-methyl-phenyl)-2-bromo-pentanone-(l) (B.P. 112115 C. at 0.2 mm. Hg) were reacted with 10.5 gm. of pyrrolidine, yielding 9 gm. of the a-pyrrolidino ketone of the formula having a boiling point of 116118 C. at 0.15 mm. Hg. Its hydrochloride was obtained in the form of a colorless crystalline substance having a melting point of 164 C. after recrystallization from acetone.

EXAMPLE 9 Preparation of 1-phenyl-2-pyrrolidin0-nonan0ne-(1 28 gm. of pyrrolodine were added dropwise to a solution of 30 gm. of 1-phenyl-2-bromo-nonanone-(1) (B.P. 138-140 C. at 0.1 mm. Hg) in 100 cc. of benzene, accompanied by stirring. After all of the pyrrolidine had been added the reaction mixture was then worked up as described in Example 1 (a). The yield was 17 gm. of the a-pyrrolidino ketone of the formula having a boiling point of 152 C. at 0.1 mm. Hg.

EXAMPLE 10 Preparation of ot-pyrrolidino-valerophenone -oo-oH-om-om-orn W :3 having a boiling point of 118 C. at 0.3 mm. Hg. Its hydrochloride had a melting point of 162 C. after re crystallization from acetone.

The a-chloro-valerophenone starting compound in the above procedure was obtained in the following manner: Chlorine was introduced for thirty minutes into a solution of 16.2 gm. of valerophenone in cc. of carbon tetrachloride while exposing the solution to the light of a 1000-watt electric bulb. Thereafter, the reaction mixture was refluxed for forty minutes, the carbon tetrachloride was evaporated and the residue was distilled. 13 gm. of a-chloro-valerophenone were obtained in the form of a liquid having a boiling point of 126-128 C. at 12 mm. Hg.

EXAMPLE 11 Preparation of I-phenyl-Z-pyrr0Iidino-hexanone-(1) Q-o o-( ;H(onn3-cH= 1 having a boiling point of 128129 C. at 0.45 mm. Hg. Its hydrochloride is a colorless crystalline substance having a melting point of 139 C. after recrystallization from acetone.

EXAMPLE 12 Preparation of a-(2-methyl-pyrr0lidino)-valer0phen0ne A solution of 9.6 gm. of a-bromo-valerophenone in 20 cc. of benzene was added dropwise to a solution of 7 gm. of Z-methyl-pyrrolidine in 30 cc. of benzene, accompanied by stirring. After all of the a-halo ketone solution had been added the reaction mixture was stirred for four hours at 40 C. Thereafter, the reaction mixture was worked up as described in Example 1 (a). The yield was 7 gm. of the a-pyrrolidino ketone of the formula having a boiling point of 127-128 C. at 0.2 mm. Hg. Its colorless hydrochloride had a melting point of 133-134 C. after two recrystallizations, first from ethyl acetate and then from acetone.

The compounds embraced by Formula I and their nontoxic, pharmacologically acceptable acid addition salts are useful in that they exhibit excellent central nervous system stimulating as well as hypertensive activities, coupled with low toxicity. With respect to their stimulating efi'ect upon the central nervous system the compounds of the present invention are anywhere from 10 to 40 times as effective as piperidino lretones of analogous or related structure.

For therapeutic application the compounds according to the present invention are administered perorally or parenterally, preferably in the form of their non-toxic pharmacologically acceptable acid addition salts. Typical examples of such salts are the following: Hydrochlorides, sulfates, phosphates, hydro'bromides, methane sulfonates, tartrates, maleates, citrates, phthalates and the like.

The average single dose of the compounds, for example )f 1-phenyl-2-pyrrolidino-pentanone-(l) hydrochloride, which has been clinically tested, is -50 mgm., preferrbly mgm. for adults. The average daily dose of the 331118 compound is 20-100 mgm. preferably mgm. for rdults. For peroral or parenteral administration the compounds of the present invention are advantageously in- :orporated as active ingredients into dosage unit composi- :ions, of which the following are illustrative examples. The parts are parts by Weight unless otherwise specified.

EXAMPLE 13 Tablets The tablets are compounded from the following ingredients:

Parts l-phenyl-2-pyrrolidino-pentanone (1) hydrochloride 20.0 Lactose 150.0 Potato starch 16.0 Stearic acid 4.0 30m starch 20.0 ['alcum 10.0

Total 220.0

ingredient.

EXAMPLE 14 Coated pills The pill core is compounded from the following ingredients:

Parts 1-phenyl-2-pyrrolidino-pentanone (1) hydrochloride 30.0 Lactose 140.0 Potato starch 16.0 Stearic acid 4.0 Corn starch r 20.0 Talcum 10.0

Total 220.0

Compounding procedure: The pill core is formed in the same manner as the tablets in Example 13. There after, the pill cores, each weighing 220 mgm. and containing 30 mgm. of the active ingredient, are coated in the customary manner with a thin shell consisting essentially of talcum and sugar which is then polished with beeswax. Total weight of each coated pill: about 350 mgm.

EXAMPLE 15 Ampules The contents of the ampules are compounded from the following ingredients:

Parts 1-phenyl-2-pyrolidino-pentanone (1) hydrochloride 10.0 Sodium phosphate, sec. 5.0 Sodium chloride 14.0

Double-distilled water (by vol.) q.s.ad 2000.0

Compounding procedure: The m-pyrrolidino 'ketone salt, the sodium phosphate and the sodium chloride are dissolved, under an atmosphere of nitrogen, in a sufiicient amount of the double-distilled water, and the resulting solution is then diluted with the remaining amount of water to the desired volume. The finished solution is filtered until free from suspended particles. It is finally filled into 2 ml. ampules in an atmosphere of nitrogen, which are sterilized for 30 minutes at C. Each ampule contains -10 mgm. of active ingredient.

EXAMPLE 16 Drops The drop solution is compounded from the following ingredients:

Parts 1-phenyl-2-pyrolidino-pentanone (l) hydrochloride 1.5 Saccharin-sodium 0.2 Sugar 20.0 p-Hydroxy-benzoic acid methyl ester 0.07 p-Hydroxy-benzoic acid propyl ester 0.03 Orange flavoring 0.5 Ethanol, pure, (by vol.) 15.0 Distilled water, (by vol.) q.s.ad 100.0

Compounding procedure: The a-pyrrolidino ketone salt, the saccharin-sodium and the sugar are dissolved in a sufficient amount of distilled water (Solution A). The p-hydroxy-benzoic acid esters and the orange flavoring are dissolved in the ethanol (Solution B). Solution B is added, while stirring, to Solution A and the resulting solution is diluted with distilled water to the desired volume. The finished solution is then filtered until clear. Each ml. of solution (about 15 drops) contains 15 mgm. of active ingredient.

While I have illustrated my invention with the aid of certain representative specific embodiments, it will be readily apparent to others skilled in the art that my invention is not limited to those embodiments. Thus, it is obvious that in Examples 13 through 16 any of the other compounds embraced by Formula I or their non-toxic acid addition salts may be substituted for the l-phenyl-Z- pyrrolidino-pentanone-(1) hydrochloride and that the concentration of the active ingredient and the nature of the inert carriers in the illustrative dosage unit compositions may be varied to suit the particular requirements. In addition, other changes and modifications may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A compound selected from the group consisting of u-pyrrolidino ketones of the formula wherein and their non-toxic, pharmacologically acceptable acid addition salts.

9 It) 2. A compound selected from the group consisting 5. 1-phenyl-2-pyrrolidino-pentanone-(1). of a-pyrrolidino ketones of the formula 6. 1-phenyl-2-pyrrolidino-hexanone-(1).

R 7. 1- (phydroxy-phenyl)-2-pyrrolidino-pentanone-( 1 8. 1- (m-methyl-phenyl)-2-pyrrolid ino-pent-anone-( 1 CO-CHR' 5 9. A compound selected from the group consisting of (A) substituted u-pyrrolidino-valerophenones of the l N following formula R" o R--ii-or-omom-cm wherein N R is selected from the group consisting of hydrogen, lower alkyl, lower alkoxy, hydroxyl and halogen, I

R is alkyl of 2 to 8 carbons, inclusive, and

R" is selected from the group consisting of hydrogen wherein R is a member selected from the class conand lower alkyl, sisting of chlorine, methyl and methoxy, and and their non-toxic, pharmocologically acceptable acid giogs gfglgf fifi y aCcepmble acld addl' addition salts.

. 10. a-Pyrrolidlno-p-chloro-valerophenone. 3. A compound selected from the group consisting of wpyrrolidino ketones of the formula Ph:I11.onI'eIydfOChlOI1d6 of a-pyrrolidmo-p-chloro valero- R 12. a-Pyrrolidino-p-methyl-valerophenone.

\ 13. Hydrochloride of a-pyrrolidino-p-methyl-valero O0 (|3H R' phenone.

N 14. a-Pyrrolidino-p-meth0Xy-valerophenone.

H 15. Hydrochloride of rx-pyrrolidino-p-methoXy-valero- R phenone. References Cited by the Examiner wherein UNITED STATES PATENTS R is selected from the group consisting of hydrogen, 3,001,910 9/1961 Schutte 16755 methyl, methoxy, hydroxyl and chlorine, R is alkyl of 2 to 7 carbon atoms, inclusive, and FOREIGN PAFUEFITS R" is selected from the group consisting of hydrogen 765,544 1/1957 Great Bummd :5? methyl h l 11 b1 d ALEX MAZEL, Primary Examiner. an en non-toxic, p armaco o ica y accepta e -ac1 additions salts. N. S. RIZZO, Examiner.

4. 1-phenyl-2-pyrro1idino-butanone-(l). JOSE TOVAR, Assistant Examiner, 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF A-PYRROLIDINO KETONES OF THE FORMULA 